The present invention relates to controlled release gemfibrozil formulations. In particular, the present invention is directed to formulations having both immediate and controlled release of gemfibrozil.
Gemfibrozil, or 5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid, is a widely used antihyper-lipoproteinemic agent. While apparently absorbed throughout the gastrointestinal tract, maximum absorption appears to occur in the upper gastrointestinal tract, notwithstanding the poor solubility of the drug at acidic pH's.
In recent years, for patient convenience, it has become desirable to provide controlled release formulations. In self-medicating patients, where efficacious blood serum levels of the active ingredient are imperative, controlled release formulations are particularly useful. In addition, controlled release formulations are useful for those patients who may easily forget to take medication.
One solution for providing controlled and/or extended release of gemfibrozil is set forth in commonly-assigned U.S. Pat. No. 4,925,676. This reference discloses a compressed disintegratable tablet prepared from a gemfibrozil formulation containing a mixture of two separate granulations. The first granulation is prepared with at least one acid-disintegratable binder while the second granulation is prepared by regranulating the first granulation with an alkali-disintegratable ingredient.
An alternative solution for providing extended release of gemfibrozil is set forth in commonly-assigned U.S. Pat. No. 4,927,639. This patent discloses a compressed tablet containing a disintegratable formulation of gemfibrozil prepared from a mixture of a first and second granulation. The first granulation contains finely divided particles of pure gemfibrozil granulated with at least one cellulose derivative. The second granulation contains finely divided particles of pure gemfibrozil granulated with a pharmaceutically acceptable water soluble or insoluble polymer which are then uniformly coated with a pharmaceutically acceptable methyl (meth) acrylate copolymer.
In spite of the above-described efforts, it would be advantageous to provide immediate and controlled release gemfibrozil formulations which do not require the labor and production costs associated with preparing multiple granulations. The ability to provide a single granulation which accomplishes both release patterns would result in savings in both time and manpower.
It is therefore an object of the present invention to provide a formulation of gemfibrozil prepared from a single granulation which provides a loading dose and controlled release of the therapeutic agent.